I did some digging in the (online) library, and came up with the attached text from a history of Ilford published by G. B. Harrison in the Proceedings of the Royal Society in 1953.

W. de W. Abney (later "Captain Abney", later still "Sir William Abney") published several interesting papers in th Proc. Royal Soc. in the 1880s and 1890s. He says that analine dyes were tried in collodion emulsions, but were not very successful. He states that the best dyes were the ones most easily bleached (which makes sense from a modern understanding of dye sensitisers). The analine dyes were of course famous for their colour fastness.

Finally, the best explanation I have yet read of how development centres form in a halide crystal and how a dye molecule contributes to the process (as well as what reciprocity failure is and how it occurs) turned up in a beautifully-written and classic paper by Gurney and Mott. Recommended if you have access to a research library: